In recent years, air conveyors have become popular for conveying lightweight articles, such as beverage containers and the like, both during the manufacturing of the containers and during filling operations. Such conveyors have enjoyed considerable success because they allow the containers to be conveyed at substantially higher speeds thus improving the overall efficiency of conveying such containers during various operations. These air conveyors utilize numerous types of structures to support and to secure the deck plate to the conveying apparatus.
Hilbish et al., U.S. Pat. No. 5,466,096, teach an air conveyor device with a plenum chamber having a perforated deck plate, side walls, and a hold down with holes of an area density sufficiently low to pressurize an enclosed article transport zone. The sidewalls include brackets for mounting doors which may be opened to remove damaged articles. The deck plate is mounted to cross supports by countersunk rivets.
Ingraham et al., U.S. Pat. No. 5,222,840, teach a double plenum air conveyor/accumulator. The conveyor has an elongated primary plenum and one or more elongated body members disposed over and in communication with the primary plenum through openings in a bottom wall of each body member. Each body member defines a secondary plenum between a top deck and the bottom wall. A plurality of cross members are employed to provide stiffening to the top deck of the conveyor.
Wiseman et al., U.S. Pat. No. 4,744,702, disclose a modular air conveyor construction comprising standardized side, bottom, and top walls adapted to be assembled together at the point of use, if so desired, to produce a conveyor section. The bottom and top walls can be provided in varying widths, and the side walls are configured to receive and hold the top and bottom walls. Further, the bottom and top walls may have brackets mounted thereon for attaching auxiliary elements such as guide rails or top covers, and to receive splice plates and other elements. The side walls are held together by means of spacers which may take the form of tie-rods. The tie-rods may be provided with a vertical support plate which engages the underside of the top wall to provide central support thereto.
Hassan et al., U.S. Pat. No. 4,165,132, disclose pneumatic control of the motion of objects suspended on an air film. This reference discloses a piece of air track including a plurality of manifolds which communicate with thin passages and which, in turn, communicate with objects to be conveyed by the pressure of air passing through the passages.
Sanders, U.S. Pat. No. 3,475,058, discloses a conveying apparatus including a support structure which forms first and second plenum chambers below a conveying surface.
The foregoing inventions are suitable for their intended purposes. However, in order to provide the required deck plate support for those conveyors which utilize deck plates having complex louver patterns, it is necessary to provide a support structure which provides continuous support to the deck plate both laterally across the deck plate and longitudinally along the length of the deck plate. This continuous support is necessary because deck plates having complex louver patterns are normally constructed of a relatively thin gauge metal, such as stainless steel, which can become warped or deformed when installed on an air conveying device. Additionally, the deck plate can become warped or deformed due to many external factors such as stresses produced on the deck plate due to moving the deck plate from one location to another, an uneven floor under the conveyor, or due to temperature changes. Also, when manufactured, the deck plate may not be completely planar which will result in the formation of bumps or undulations on the deck plate. Even the slightest imperfections in a deck plate which causes the deck plate to not be completely planar results in irregular and uncontrollable conveyance of articles thereupon. Therefore, it is imperative that the deck plate support structure provide the required continuous lateral and longitudinal support to overcome any imperfections in the shape of the deck plate.
Furthermore, the support structure must not unnecessarily restrict the flow of air through the louvers which communicate with the plenum of the deck plate. Restricted air flow on any portion of the deck plate results in irregular air pressures along the upper surface of the deck plate which, in turn, causes containers on the deck plate to not be conveyed in a controllable and uniform manner.